no ive been busy with restoring and finishing a Smart Brown Model A Toolroom Lathe. got this little beauty for only £300, cost me £55 to move it on palate from Essex to durham. took me 2 weeks to strip and recondition.You had any luck with getting this fixed
Ive stripped the machine today and got my head around its innerds.... I was shocked atits simplicity compared to something like a Murex Autolynx. All I basically have within this machine on the welding side is two transformers and a set of recifyers and that's it. On the control side their is a step down transformer taking 240v to 24v and a couple of solenoids and contactors.Hi I have similar machine and had a very similar problem were the wire would resemble a sparkler burn spatter and pop but no proper penetration.turn out to be poor connection on the dinse socket for earth on the front of m/c causing arcing and so poor continuity but also check connections round the rectifier in and out.
done a little troubleshooting on it just now, no further forward, she all seems fine connection wise.You had any luck with getting this fixed
Im not sure it is an upgrade.. when I look at it within circuit you get 240 mains in, which goes to a smallish three layered transformer behind the two large main transformers and im guessin this is a stepdown transformer as everything it powers from there on seems to be 24v. also thi bridge rectifier with the red leads takes its input from this smaller transformer and outputs from this bridge rectifier then power the air line 24vdc solenoid, also to a contactor which then powers the 24vdc wire feed motor and last of all it has a wire going to the control pcb, not sure if that's an input or output though???Also third pic down seems to show some one has modified this mig with a bridge rectifier(square box four connections) and all the red wiring.not uncommon to find modifications as I added capacitors to mine to smooth out the arc a bit.
just to cover something that I may be understanding wrongly.. Rectifyers all 8x laid out within this plate layer (bridge rectifier) I had always been of the belief that if only one within this arrangement went bad then the whole arrangement wouldn't put out anything at all. though from what im learning here you guys seem to be saying that one or two bad ones could be causing this low output? So it will kinda still work even with one or two bad diodes? is this correct?Cuma - I have replied to your email. For anyone else with this fault, replace the main rectifier - 99% certain that this is your problem. Individual diodes are virtually impossible to replace and testing each diode is very difficult as the whole assembly must be stripped and getting it reassembled correctly is a nightmare. Save time and grief, buy a replacement if you can find a suitable part. It's unlikely that you'll get spares from Nu-tool but I could be wrong. Always note where each wire goes before removal and check polarity too. Getting any of this wrong could stuff the machine and pcb totally.
Dave
could you advise on the following??? ihave seen some relative cheap assemblies for rectifier brides that are simple bolt on units.. BUT!!!! my welder seems to have two parallel double plate bridge assemblies using 8 diodes. you can buy these units as double plateswith 4 diodes but not 8 diodes. the only ones ive seen using two parallel 8 diode layouts are 4 plate units. PLUS!!!! one other consideration is the way my unit is wired up to these diodes. it utilises 4 connections. 3 transformer and one to torch. so which rectifier assembly from the below supplier is suitable.Your meter will only check continuity at low voltage but those connections may break down when trying to carry high currant so the bolted connections will need loosening and tightening back up.that' exactly how I fixed mine and am still not sure if it was rectifier or earth lead socket connections that was at fault.yes they are extremely simple machines in their design not much to go wrong that can't be replaced.
Ive just tested each if the 8x diodes in the bride and they all tested identical 485 in one direction and nothing in the other. which is what a diode test should do if im right in thinking. No reading in either direction would indicate open diode, and a reading in both directions is a short diode, right????Cuma - I have replied to your email. For anyone else with this fault, replace the main rectifier - 99% certain that this is your problem. Individual diodes are virtually impossible to replace and testing each diode is very difficult as the whole assembly must be stripped and getting it reassembled correctly is a nightmare. Save time and grief, buy a replacement if you can find a suitable part. It's unlikely that you'll get spares from Nu-tool but I could be wrong. Always note where each wire goes before removal and check polarity too. Getting any of this wrong could stuff the machine and pcb totally.
Dave